Hoechst Aktiengesellschaft

Gunter Reichert

Hermann Niermann

Franz Mainzer

Friedrich Neumann

Johannes Krause

Hans Ebert

Kurt Lehmann

Eberhard Preisler

Hans-Werner Stephan

Herbert Panter

Gerhard Nolte

Hermann Klein

Hans-Dieter Benscheidt

The invention relates to a method for controlling and optionally regulating the level of liquid P.sub.2 S.sub.5 in a cooling device. To this end, an inert gas is introduced into the cooling apparatus arranged in inclined position. More particularly, the inert gas is introduced into the cooling apparatus' lower end portion through an inlet opening thereinto near a P.sub.2 S.sub.5 -feed inlet, and forced to bubble through the liquid P.sub.2 S.sub.5. The pressure difference which establishes in accordance with the P.sub.2 S.sub.5 liquid level in the device is measured and variations in the respective pressure difference are utilized for regulating the supply of liquid P.sub.2 S.sub.5 to the cooling device so as to maintain a predetermined liquid level therein.

Method for controlling and optionally regulating the level of liquid

The invention provides a process and an apparatus for removing molten phosphorus pentasulfide, via an overflow, from a reactor, wherein phosphorus is reacted with sulfur at temperatures higher than 300.degree. C. To this end, the reactor is supplied with phosphorus and sulfur from dosing vessels which are given the dimensions necessary (a) to receive the quantity of phosphorus and sulfur, respectively, which are required to produce phosphorus pentasulfide with a preselected quantitative ratio of P:S, (b) to provide a total filling volume corresponding to that of a P.sub.2 S.sub.5 -receiving tank. The quantity of the phosphorus and sulfur feed materials in the respective dosing vessels is in each case fully emptied into the reactor and a corresponding quantity of molten P.sub.2 S.sub.5 is simultaneously discharged directly from the reactor, via the overflow, into the respective P.sub.2 S.sub.5 -receiving tank, whose filling volume exactly corresponds, to that of the dosing vessels.

Process for removing molten phosphorus pentsulfide from a reactor

Phosphorus pentasulfide of low reactivity is made by solidifying molten phosphorus pentasulfide on a cooling cylinder that delivers the solidified product at a temperature of 150.degree. to 220.degree. C., and that product is immediately introduced into a heat-insulated container and freed therein from its immanent or sensible heat by cooling at a rate of at most 30.degree. C. per hour without the expenditure of any energy to control the cooling.

Preparing P.sub.2 S.sub.5 of low reactivity

The disclosure provides an electrolytic cell sealed in gas-tight and liquid-tight fashion. The cell is comprised of a box-shaped cell tank open at its top and provided with at least one intake duct, at least one overflow duct and at least one discharge duct. A cover is placed on the cell tank and two opposed flanges receiving electrode supporting frames are secured to the inside of the cell tank near the upper end thereof. A chemically resistant and electrically insulating coating is applied to the inside of the cover and cell tank and a plurality of semi-circular recessed grooves spaced apart from each other are formed in the upper rim portion of at least one of the side walls of the cell tank, the recessed grooves receiving semi-circular current beams projecting outwardly. A first elastic packing structurally conformed to the upper rim portion of the cell tank including the recessed grooves is placed thereon and a second elastic packing arranged at the underside of the cover co-operates with the upper side of the current beam and the first elastic packing whereby the electrolytic cell becomes gas tightly sealed. A main current rail is arranged to run outside the cell tank laterally with respect thereto and so as to be spaced therefrom, the rail providing large contact areas supporting the projecting end of the current beams. The electrode supporting frames and the current beams are electrically conducting inside the electrolytic ce

Electrolytic cell

The invention relates to an apparatus for making P.sub.2 S.sub.5 comprised of a plurality of reactors connected by pipe structures to a collecting tank which is common to all of them. By means of partitions, the cooling tank is subdivided into a plurality of separate chambers. Outlet pipes open thereinto and terminate in collecting devices. The pipe structures running to the collecting tank are pivotably arranged above the various chambers and permit liquid P.sub.2 S.sub.5 to be introduced thereinto at will.

Apparatus for making phosphorus pentasulfide

Method and apparatus for controlling and optionally regulating the level

The invention provides a process wherein a mixture prepared from starting materials comprised of P.sub.2 S.sub.5 of high reactivity and low reactivity, respectively, is converted to phosphorus pentasulfide of predetermined reactivity lying between that of the high reactivity P.sub.2 S.sub.5 and that of the low reactivity P.sub.2 S.sub.5 starting materials. To this end, the starting materials are mixed in quantitative proportions which are selected in accordance with the respective reactivity of the starting materials and the resulting mixture is ground.

Production of phosphorus pentasulfide of predetermined reactivity

The reactivity of phosphorus pentasulfide produced by reacting phosphorus and sulfur at a temperature higher than the melting point of phosphorus pentasulfide and allowing the resulting melt to cool and solidify on a cooling device is improved. To this end, liquid phosphorus pentasulfide is placed on, or introduced into, a cooling device; an upper liquid P.sub.2 S.sub.5 -layer portion A is separated immediately from a solidified lower P.sub.2 S.sub.5 -layer portion B which is in direct contact with the cooling surface area of the cooling device; the upper P.sub.2 S.sub.5 -layer portion A is recycled to a P.sub.2 S.sub.5 melt; the lower P.sub.2 S.sub.5 -layer portion B is removed from the cooling device and collected as final product; the reactivity of the collected P.sub.2 S.sub.5 -layer portion B is increased to the same extent as the quantitative ratio of the P.sub.2 S.sub.5 -layer portion A to the P.sub.2 S.sub.5 -layer portion B is increased.

Growing community of inventors

Bornheim-Merten, Germany

Gunter Reichert